In medical intervention there is a trend towards very large screens (e.g. 56 inch) in medical exam rooms. These large screens replace current screen configurations of 17 or 19 inch screens in a 2×2 or 2×3 arrangement. There is also a desire to be able to control the applications that are displayed on the large screens from the operating table instead of just from a separate control room. On the one hand this greatly improves the freedom of displaying information for the physician while standing at an operating table. On the other hand, the handling of user interfaces by moving a pointing device (like an airmouse, gyromouse, Wii-like remote, etc.) in order to move a cursor on a very large screen might create some problems.
One possible problem might be that the user sometimes loses track of where the cursor on the screen is positioned, because it is hard to locate the cursor on the large screen.
Another handling problem might occur at the edges of the screen when the cursor hits the edge of the screen.
One way of overcoming these problems is by making the pointing device “absolute”. This means that there is always a direct relation between the orientation or position of the pointing device and the position of the cursor on the screen. The advantage of this approach is that from the orientation or position of the pointing device it is always clear where the cursor on the screen is located. However, absolute devices also have some drawbacks.
With these absolute pointing devices, moving the cursor very accurately becomes difficult, because the transfer of device motion to cursor motion is fixed. This means that hand movement (shaking) is directly coupled to the cursor movement. This means also that large movements on the screen require large device (hand, arm) movements. Furthermore, this has the effect that an absolute pointing device requires maintaining a certain orientation of the pointing device without being able to change posture, which can be very tiring. For instance, it is not possible to drop the arm and continue pointing from there.